(1) Field of the Invention
This invention relates to an apparatus which continuously applies an agricultural chemically-impregnated chemical filament to soil.
(2) Description of the Prior Art
Herbicides are usually applied as sprays in water or oil, or as dry granules. A system of applying liquid chemicals to the tops of plants by rope wicks was recently developed, but herbicides are basically applied by spraying over the top of plants or under the plant canopy toward the base of crop plants. When herbicides are sprayed on the soil before planting and emergence of crop plants, they may be either left on the soil surface or physically incorporated into the soil. Their characteristic phytotoxic properties may be altered by surfactants, such as sticking and wetting agents, added to their formulations or spray solutions, or by the kind of formulation used, such as granular formulation in place of emulsifiable concentrate. Other techniques that are known but seldom used in the art of applying herbicides include the injection of liquid or gaseous formulations directly into the soil (with or without the use of an impervious shield such as a plastic sheet to retain the vapors in the soil) and the use of bars of wax containing the herbicide to rub over the tops of weeds.
Hardy (U.S. Pat. No. 4,187,638) and Dale (U.S. Pat. No. 4,219,964) relate to application of liquid chemicals by rubbing foilage and tops of plants with segments of chemical-soaked rope carried from plant-to-plant but germinating seed, plant roots, and shorter plants cannot be treated by this means due to their location in or near the soil.
Green (U.S. Pat. No. 3,864,142) relates chemical-impregnated fabrics for laying on the soil surface, but this means is seldom used since effectiveness of chemicals applied in this manner deteriorates rapidly under the influence of sun, wind, and rain.
Zitko (U.S. Pat. No. 3,065,605), Brugel (German Pat. No. 826,516), and Crepet (French Pat. No. 2,302,017), relate means of placement of seed-affixed tapes in soil with massive machines having a multiple of moving parts, and power-driven gears and press-wheels. Although application of agricultural chemicals by this means is conceivable, costs are prohibitive even where the machines are available, and for gardners and small, non-mechanized farmers whose agronomic practices depend largely on the use of hand tools, the required mechanization is unacceptable. None of the prior art teaches technology similary to the instant invention.